GroEL Protein (Heat Shock Protein 60) of Mycoplasma gallisepticum Induces Apoptosis in Host Cells by Interacting with Annexin A2.

Abstract

is an avian respiratory and reproductive tract pathogen that has a significant economic impact on the poultry industry worldwide. Although membrane proteins ofspp. are thought to play crucial roles in host interactions, very few have had their biochemical function defined. In this study, we found that the GroEL protein (heat shock protein 60) ofcould induce apoptosis in peripheral blood mononuclear cells, and the underlying molecular mechanism was further determined. The GroEL gene fromwas cloned and expressed into facilitate the functional analysis of recombinant protein. The purified GroEL protein was shown to adhere to peripheral blood mononuclear cells (PBMCs) and DF-1 cells and cause apoptosis in PBMCs. A protein pulldown assay coupled with mass spectrometry identified that annexin A2 possibly interacted with GroEL protein. Coimmunoprecipitation assays confirmed that GroEL proteins could bind to annexin A2, and confocal analysis further demonstrated that GroEL colocolized with annexin A2 in HEK293T cells and PBMCs. Moreover, annexin A2 expression was significantly induced by a recombinant GroEL protein in PBMCs, and knocking down annexin A2 expression resulted in significantly reduced apoptosis. Taken together, these data suggest that GroEL induces apoptosis in host cells by interacting with annexin A2, a novel virulence mechanism inOur findings lead to a better understanding of molecular pathogenesis in.